"Falcon Heavy at the Cape," crowed Musk in his Twitter post at 1:57 a.m. The team recently completed production on its 400th Merlin 1D engine, which the founder call the latest phase of SpaceX's rocket engine that powers Falcon 9 to space, he Tweeted Thursday.

The Falcon Heavy, which launched from the same NASA pad as the Saturn V Apollo 11 moon rocket, is expected to take off on its maiden voyage in January 2018.